The present invention generally relates to an improved data transmission technique, more particularly relates to a technique for managing the transmission of data sampled in real time, and even more particularly relates to a buffer management technique utilizing agents for use in data transmission.
In many situations, data sampled or otherwise acquired in real time, or in a manner analogous to real time acquisition, cannot be forwarded immediately after acquisition. For example, due to the demands of the application being served or the requirements of the associated communication environment, data may have to be held or queued until a transmission opportunity arises. In a time division communication environment, data may have to be stored until the arrival of a time slot assigned to the node or to the node""s intended receiver. When the appropriate assigned time slot arrives, the data will be transmitted.
In certain applications, the latency period added by the time spent waiting for a transmit opportunity is not significantly detrimental to the desired performance of the system. In other applications, however, the added latency can result in diminished performance or even catastrophic failure. For example, this type of latency may be of little or no consequence to the performance of a statewide temperature monitoring and reporting network. In applications involving the remote control of high-speed vehicles, however, the vehicle can travel a significant distance during a delay of just a few milliseconds. Thus, due to latency, the actual location of the vehicle may be significantly different than the location information being presented to an operator. Consequently, guidance errors can result.
FIG. 1 depicts the data management technique typically employed when sampled data is to be transmitted. A factor of interest is sampled 100 pursuant to some schedule, cycle or other triggering event. Each sample is then queued 102 into storage. The storage component operates as a first-in-first-out system (FIFO). As each transmit opportunity arises, the appropriate sample is transmitted 104. Since a FIFO system is used, the oldest stored sample will be the next to be transmitted. Thus, the sample being transmitted may be substantially different than the sample being currently taken. As a result, the sample being transmitted may not adequately represent the actual state of the system at the time of transmission.
Consequently, there exists a need for a data management technique that will reduce latency. A flexible system that can capture a sample closer to the time of its transmission is needed. These needs and others are fulfilled by the inventions disclosed in the following description.
It is an object of the present invention to provide an improved data management technique for data communication.
It is a feature of the present invention to utilize an agent that retrieves a sample just prior to the time of communication.
It is an advantage of the present invention to reduce latency in the communication of sampled data.
The present invention involves an improved buffer management technique for data communication. It is carried out in a xe2x80x9cdelay-reducedxe2x80x9d manner in the sense that filled data packets are not queued for later transmission. Rather, an agent retrieves a data sample at a point just prior to transmission and inserts it into the packet. In another embodiment, one or more agents are queued along with a reservation of communication space, then, at a time just prior to transmission, the agent or agents are activated to retrieve and insert data into the communication packet.